Aircraft with groukd effect type landing gear



March 3, 1970 'r. n. EARL Erm- AIRCRAFT WITH GROUND EFFECT TYPE LANDINGGEAR Original Filed March 17, 1965 8 Sheets-Sheet 1 INVENTORS T. 0. EARLBY W. J. EGGINGTON @MIQMI A TTOPNEYS March 3, 1970 1'. o. EARL EI'ALAIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR Original Filed March 17,1965 8 Sheets-Sheet 2 INVENTORS T. 0. EARL BY W. J. EGGINGTON ATTOB/VEYS Much 970 I. o. EARL ETAL Re. 26,812

AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR Original Filad llarch 17.1965 8 Sheets-Sheet 5 RE ACT ION SURFACE TAKE OFF RUN TAXIING ATTITUDELIFTOFF E t o- 8 35 INVENTORS 1'. o. EARL y w. J. EGGINGTON M,M@uwATTORNEYS March 3, 1970 T. D. EARL ETAL Re. 26,812

AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR Original Filed larch 17.1965 e Sheets-Sheet 4 S N m m T. 6 m m v 3 m EE J on N T T w A TTOPNEYSMarch 3, 1970 T. D. EARL ETAL Re. 26,812

AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR Original Filed larch 17,1965 8 Sheets-Sheet 5 IN VEN TOR$ T. D. EARL W. J. EGGINGTON a 640 4, 6-ay 6M A TTOPNEYS M 1970 r. o. EARL E'rm.

AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR 8 Sheets-Sheet 6 JriginalFiled larch 17. 1965 INVENTORS T, D. EAR L em I @m w. J. EGGINGTONRNE'YS March 3., 1970 1'. D. EARL El AL Re. 26,812

AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEAR Original I'ihd larch 17.1965 8 Sheets-Sheet 7 qXE aid 5E IN VEN'TORS T. D. E ARL BY W. J.EGGINGTON A TTORNEYS Mar ch 3, 1970 1'. o. EARL ET AL AIRCRAFT WITHGROUND EFFECT TYPE LANDING GEAR Original Filed larch 17, 1965 8Sheets-Sheet 8 1 N VENTORS w T 6 LM mm E T W Y B A TTORNEYS UnitedStates Patent 0 l 26,812 AIRCRAFT WITH GROUND EFFECT TYPE LANDING GEARThomas Desmond Ear], Niagara-on-the-Lake, Ontario, Canada, and WilfredJames Eggington, Claremont, Calih, assignors to Bell AerospaceCorporation, Wheatfield, N.Y.

Original No. 3,275,270, dated Sept. 27, 1966, Ser. No. 440,437, Mar. 17,1965. Application for reissue July 1, 1968, Ser. No. 746,217

Int. Cl. B60v 3/08 US. Cl. 244101 21 Claims Matter enclosed in heavybrackets appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the additionsmade by reissue.

ABSTRACT OF THE DISCLOSURE The fuselage of an aircraft is provided withan airinflutable elastic cell structure which is normally retracted intoa position in which it is compatible with the aerodynamic shape of thefuselage. When inflated, the cell structure balloons downwardly toprovide and define an air cushion space laterally bounded by theinflated cell structure. The cell structure is provided with air outletopenings around its botlom contour to permit air to blast downwardly andfeed the air cushion space for supporting the aircraft during take-ofiand landing.

This invention relates to aircraft, and more particularly to an improvedlanding gear means for winged airplanes whereby an improved landing, andtake-off and taxiing technique is made available to the industry. Theinvention is particularly advantageous for embodiment in high speedlanding and take-off type airplanes. The term airplane as used herein isintended to relate to any form of aircraft having lift wing deviceswhich are either truly fixed to the fuselage or are perhaps adjustablethereon so as to vary the sweep or incidence angles thereof, but in anycase operating in the mode of the so-called fixedwing type airplanewhich lands and takes off at relatively low angles to the land or watersupport surface, as distinguished from VTOL or helicopter type aircraftor the like.

Thus, a primary object of the invention is to provide an improvedlanding gear system for airplanes which functions during take-oil andlanding and taxiing operations, as well as during flight operations, allunder pilotcontrol and in improved manner.

Another object is to provide an undercarriage system as aforesaidenabling airplanes to land and take-oli with ease and facility fromeither conventional run-ways, or soft or only generally level andotherwise unprepared land surfaces, or water surfaces.

Still another object of the invention is to provide an airplaneundercarriage system such as will make feasible and practicable highspeed take-offs and landings on either conventional or inexpensivelyprepared unpaved runways or the like, or even on unprepared butgenerally level land, bog, marsh, snow or ice surfaces, or the like.

Another object is to provide an improved system as aforesaid whereby anairplane embodying the invention may with ease and safety land andtake-oil from bodies of water without requiring the aircraft to embodythe structures of conventional amphibian or flying boat" type aircraft.

Another object is to provide an undercarriage system as aforesaid whichdistributes landing shock and pressure loads over large underside areasof the fuselage, thereby eliminating the need for structuralconcentrations in the Ill) Reissued Mar. 3, 1970 aircraft fuselage suchas are required to transfer the stresses generated by conventional typelanding gear systems, resulting in considerable overall weight savings.

Another object is to provide an improved landing gear arrangement asaforesaid wherein the structurally rigid parts thereof are at all timespositioned out of harms way in event of cross-wind or crash landing; andwhereby the system successfully withstands (with only negligible, or nodamage at all) landings under such severe conditions as would wreckconventional wheeled type undercarriage structures or the like.

Another object is to provide in a system as aforesaid an improvedundercarriage arrangement which will successfully withstand withoutstructural damage, lateral slip landings such as would wreckconventional wheeled type undercarriage structures or the like.

Further, it is an object of the invention to provide an improvedundercarriage system as aforesaid wherein the undercarriage devicegenerates a transient gas cushion under the aircraft when moving infriction-free manner in close proximity to the landing taxiing, ortake-off surface; thereby supporting the plane in an improved loadistribution manner relative to the land or water reaction surface, andresulting in reduced foot-print pressures" when the craft is finallysupported by the landing surface.

Another object is to provide an improved airplane undercarriage systemas aforesaid which will permit take-offs and landings in any desireddirection independently of the local wind direction.

Another object is to provide an improved undercarriage system for highspeed landing and take-off airplanes permitting simultaneous use ofparallel landing strips, thereby providing maximum traffic capacity fora given air base area.

Another object is to provide an improved undercarriage system asaforesaid which will eliminate the hazards of emergency airplanelandings on rough ground or water; and which after ditching of anaircraft operating over water will operate to keep the plane afloatand/or enable it to operate as a ground effect vehicle while reaching aposition of safety.

Generally stated, the primary objects of the invention may be attainedby providing means carried by the airplane for projecting (under pilotcontrol) one or more blasts of pressurized fluid, generally air,downwardly from the airplane against the land or water surface relativeto which the airplane is landing, taxiing, or taking off. Thus,transient cushions of pressurized air or the like are formed between theairplane fuselage and said surface, of such nature as to be capable ofholding off the airplane from actual contact with the surface as thecraft completes its landing, taxiing, or take-off run.

By way of example, and as shown in the drawing herewith, one preferredform of undercarriage system of the invention includes inflatable celldevices which in plan view are of generally annular configurations, andlocated at the belly portion of the airplane. The cells are normally(when in flight regime) deflated and nested into the airplane body toprovide an aerodynamically clean fuselage; but are inflatable to extendoutwardly and downwardly below the fuselage when being called upon tofunction as undercarriage means. Under this condition they assume theshapes of annular balloon-like elastic cushion devices circumscribingopen air-cushion holding spaces therewithin. Pressured air supply meanscarried within the aircraft are provided to discharge jets of airthrough and perimetrically outwardly of the cell devices and downwardlytherefrom in such manner as to produce peripheral jet curtains operatingto generate and retain ground eflect air cushions acting against theairplane landing surface when the airplane is in clos proximity thereto.

Hence, another object of the invention is to provide an airplaneundercarriage device as above described, including inflatable cellmembers which are dcflatable and retractable in improved manner when theairplane is in flight to conform to the contour of the airplane fuselagefor flight etficiency purposes.

Another object is to provide an undercarriage arrangement as aforesaid,wherein the pressured air supply means may be arranged to also provideboundary layer air control elfects at the external surfaces of theaircraft fuselage, for improved flight performance purposes.

More specifically, by way of example and as illustrated herewith, oneform of the invention involves the provision of one or more generallyannular-shaped resilient cell devices which form, when the airplane isin flight regime, portions of the fuselage belly skin surface; and whichare inflatable under pilot control as the airplane approaches a landingsurface so as to belly out from the fuselage, thereby providing atoroidal-shaped cell or cells extending below the fuselage. Air outletslots through the bottom surfaces of the inflated cells then permitstreams of high velocity air jet downwardly and peripherally of the cellor cells. Hence, for example when the airplane is approaching a landingit may be flown flatwise relative to the landing surface, and as itsinks toward the surface and just prior to the time the fuselage wouldotherwise come into frictional contact with the ground, there will bethereby created an air cushion or cushions under the fuselage in theareas circumscribed by the inflated cells.

As the bottom perimetral portions of the cells come within inches of thelanding surface, the air cushion effects developing therewithin andreacting against the fuselage take over the vertical support of theaircraft and its load, thereby causing the craft to skim over anyreasonably level landing surface without actual contacts therewith.Incidental to a landing, upon completion of the transition fromair-borne to ground effect support regime, the forward motion of theaircaft may be braked by reversal of the aircraft propulsion system, orby use of retro-rockets, or by the lowering of friction brake devicesagainst the landing surface, or by any other suitable means as may bepreferred. Or, alternatively, the forward motion of the craft may bebraked by pitching the craft so as to drag a rear end portion of the aircell structure against the landing surface; the air cell surface beingin this case protected by means of a wear-resistant coating or the like,as will be explained in more detail hereinafter.

The invention further contemplates novel optional modifications of thebasic system. For example, it is contemplated that the intake of air tothe fans supplying the air cells may be drawn through the aircraftfuselage skin at strategic positions therealong for boundary layer aircontrol purposes. Also, if desired the air discharging from the fans maybe arranged to be alternatively diverted to jet discharge means directedrearwardly of the craft. Thus, during all flight regimes andparticularly during climb-out, the ground effect air supply engine andfan system may be usefully employed to augment the primary propulsionsystem of the aircraft. Other novel features and specific objects of thepresent invention will also be apparent from the following specificationillustrating by way of example several possible embodiments of theinvention as shown in the accompanying drawings where- FIG. 1 is apictorial illustration of a landing and taxiing maneuver of an aircraftembodying the present invention;

FIG. 2 is a bottom plan view of an aircraft fuselage embodying one formof the invention;

FIG. 3 is a view corresponding to FIG. 2 of another form ofundercarriage arrangement of the invention;

FIG. 4 is a front-bottom perspective view of an aircraft such as shownin FIG. 3;

FIG. 5 is a composite three-positional view in side elevation, showingan airplane such as that of FIGS. 3, 4, when performing a landing andtaxiing maneuver;

FIG. 6 is a view corresponding to FIG. 5 but showing the airplane in atake-ofi' run and climb-out maneuver;

FIG. 7 is an enlarged scale fragmentary vertical section schematic viewof the undercarriage portion of the airplane when commencing a climb-outmaneuver as illustrated by the central figure of FIG. 6;

FIG. 8 is a fragmentary horizontal sectional view through a portion ofthe fuselage of the aircraft of FIGS. 37 as indicated at 8-8, FIG. 5;

FIG. 9 is a transverse vertical sectional view thereof, on enlargedscale, taken as suggested along line 9-9 of FIG. 8;

FIG. 10 is a view corresponding to the left hand side portion of FIG. 9,showing one portion of the air cell and peripheral jet device in itsground effect operative condition;

FIG. 11 corresponds to FIG. 10 but illustrates the device thereof in aninitial stage of deflation-retraction;

FIG. 12 corresponds to FIGS. l0, 11, but illustrates the device in fulldeflated and retracted condition, as when the aircraft is in normalflight;

FIG. 13 corresponds to FIG. 8 but illustrates how the air fan dischargesystem may be selectively diverted to assist in propulsion of theaircraft when in flight regime;

FIG. 14 is a vertical sectional view taken as suggested along line l414of FIG. 13;

FIG. 15 corresponds to FIG. 13 but illustrates a modified form of airfan intake arrangement; and

.FIG. 16 is a fragmentary sectional view, on enlarged scale, taken assuggested by line 1616 of FIG. 15.

As explained hereinabove, the invention may be embodied in any typeairplane; and as shown by way of example by the accompanying drawing, itmay be incorporated in an airplane comprising generally a fuselage orbody 20; wing panels 2222; empcnnage 24; and engine-prop or jet or otherpropulsion power supply means as indicated generally at 25. However, itis to be understood that the invention may be embodied in any other typeor style of airplane.

More especially, the invention is provided to comprise a pressured fluidsupply such as for example a compressed air supply device means carriedwithin the airplane body; and as shown in FIGS. 8, 9, 13, 14, 15, 16,for example, such means may comprise a pair of compressor fans 26-26driven by corresponding turbines (or other type engines) 2828. Theengines 28-28 may be fueled and arranged for pilot-control in anydesired manner, and suitable ducting is associated with the compressorfans to provide for intake of air to the compressors from any preferredpoints externally of the fuse lage, and for discharge of compressed air(when the undercarriage system is functioning) downwardly below theairplane belly in such manner as to generate therebelow a transient aircushion effect whenever the craft is in close enough proximity to alanding ground or water surface.

Thus, for example, as shown in FIG. 2, the compressed air dischargeducting may be arranged to discharge blasts. or jets of air downwardlyfrom the fuselage belly through orifices or slots as indicated at 29which are preferably arranged in bottom plan view to define a peripheralcurtain circumscribing an air cushion generating space therewithin. Forthis purpose the slots 29 are all preferably directed somewhat inwardlyso as to operate with appreciable inwardly directed thrust vectors,thereby contributing to the strength of the peripheral curtain of airwhich operates to generate the transient air cushion between thefuselage and the landing surface. Whereas FIG. 2 illustrates provisionof means for only one air cushion between the fuselage and the landingsurface, it is to be understood that the air jet orifices or slots maybe so provided as to delineate any other preferred number of air cushionareas; and that such cushions may be relatively positioned under theairplane belly or under the wings in the case of a delta wing vehicle,so as to be in any desired pattern of longitudinally and laterallyspaced relationships, in order to attain the preferred pitch and rollcontrol characteristics.

FIGS. 3-15 illustrate another form of undercarriage arrangement of theinvention wherein two, longitudinally separate, air cushion providingdevices are employed. Furthermore, in this form the air jet openings areembodied in flexible, alternately inflatable-deflatable, bal loon-likecell devices which normally nest into the aerodynamic contour of theairplane fuselage, but which when operating in undercarriage mode extendoutwardly and downwardly of the airplane fuselage belly in the form oftoroidal-shaped cells. The air jet openings per se are provided in theform of any desired shape of orifices, slots, or the like, alignedaround and under the bottom peripheries of the cell devices wheninflated. The jet openings are preferably constructed so as to directtheir air blasts inwardly as well as downwardly so as to pro videefficient curtains of air circumscri bing the air cushion generatingareas therewithin.

More specifically, FIGS. 3-15 show an airplane as above describedequipped with a pair of air cushion generating cells indicated generallyat 30 and 32, respectively. As shown at FIG. 12, these cells arenormally (when in flight regime) deflated and retracted into aerodynamicprofile conformity with the airplane fuselage when the compressed airsupply system is either inoperative, or, as

shown at FIGS. 13-15, operative but controlled to divert its dischargethrust through nozzles at the rear of the airplane for propulsionaugmentation. The cell devices 30, 32 may be constructed of any suitablyflexible sheet material as indicated at 33 which is preferably elasticin girth-wise directions, and are preferably fabricated so as toresiliently retract of their own accord into tautened,fuselage-contour-conforming condition, as shown in FIG. 12 when nocompressed air is being pumped thereinto. However, when air pressure issupplied therein (as will be explained more fully hereinafter) the cellsballoon out and downwardly below the airplane fuselage as shown in FIGS.3-15, and perhaps as best illustrated at FIG. 4.

The cells are fed with air under pressure from the fans 26-26 by meansof any suitable ducting, and as shown herein the ducting may comprisehousings 34-34 enclosing the fans 26-26 and leading to downspouts 36-36which discharge through the airplane fuselage skin into the rear endsand front ends respectively of the cells 30, 32 (FIGS. 8-14). Thus,pumping of air through the downspouts 36-36 will cause the cells toballoon out as into the configuration shown in FIGS. 10, 11. Asindicated at 40, the cells 30, 32 are slotted along their bottomfoot-print surfaces to permit jets of compressed air to blast downwardlytherefrom as shown in FIGS. 9, 10.

A valve device for the slots of each cell is provided as indicatedgenerally at 42. Each valve may, as shown herein, comprise a rubber tubeor the like formed for example to comprise a relatively pliable upperwall portion 43 joined integrally with a relatively stiffer bottom Wallportion 44; the cylinder thus foimed being constructed to normally takea set" so as to lie in flattened condition (FIGS. 11-12). Inflationtubes 46 lead into each valve device from conduits 48 takinghigh-pressure air from the high pressure stage portions of thecompressor casings; the flow of air being controlled as by a valve 49 inthe line of each air supply tube.

By virtue of this valve arrangement, wherever the airplane approaches alanding (FIGS. 1, 4, the com pressors may be operated to dischargethrough the downspouts 3636 and into the cells 30, 32, thus causing thecells to initially balloon out from the condition shown in FIG. 12 as tothe condition shown in FIG. 11. High pressure air is simultaneously letinto the tubes 46 through valves 49 so as to cause the valve cylinders42 to inflate as to the condition shown in FIG. 10. This valve "openingaction uncovers the slots so that air from the cells now blastsdownwardly through the slots as shown in FIGS. 9, 10. Note that thecurved bottom surfaces of the valve cylinders 42 induce theestablishment of the socalled coanda effect which operates to drag thedischarge air curtain inwardly and under the device, to more effectivelyfeed the air cushion generating space which is designated 50 in thedrawing. Thus the inflated cells and the curtains of compressed airblasting out of the slots 40 cooperate to build and maintain a transientair cushion under the fuselage belly wherever the latter comes intoclose enough proximity with a reaction surface as illustrated by FIGS.8, 9, 10. As shown in FIG. 9, the air feed to the cushion area 50 may besupplemented if desired as by means of a branch duct 52 leading from themain ducts and delivering downwardly through a centrally located opening54 in the fuselage (FIGS. 3, 4, 9).

It is of course to be understood that various valve and other controldevices will be employed in conjunction with the compressor engine andthe discharge ducts and the valve tubes, etc. under pilot control(either manual or automatic) to provide the pilot with all desirableselective and/or diflerential controls for these mechanisms. Hence, anairplane embodying the present invention may come in for a landing aspictured for exanple at FIGS. 1, 4, 5, relative to any surface that willreact to the ground effect or transient air cushion which develops underthe belly of the aircraft fuselage as explained hereinabove; and toprovide the requisite reaction" for support of the craft the surfaceneed not be a conventional type paved landing strip or the like. It needonly be generally level, and may comprise a body of water, or marshland, or soft dirt or sand or flat rock or snow or ice; but in any casethe craft will be held off from actual physical contact with the surfaceand will simply skim along in friction-free manner above it.

Reversal of the propulsion propellers or jet engine thrust direction, orlowering of drag brakes or the like, will then bring the craft to a haltwhile still being suspended (by a matter of inches) above the landingsurface. It may now be taxied as desired in the manner of a conventionalground effect machine. Take-off maneuvers are effected by reversal ofthe process. After loading, the craft is elevated by operation of thecompressors into its ground effect" regime, and the propulsion enginesare then brought into action to taxi the craft into the take-offmaneuver. Take-offs are facilitated because of the friction-freerelationship of the craft to the landing surface during the take-offrun. Immediately upon becoming air-borne in the airplane sense the pilotmay adjust the system controlling the compressor output so as to divertthe compressor discharge thrust through ducting directing the dischargeinto the atmosphere behind the aircraft, thus augmenting the drivingeffects of the propulsion engine system of the aircraft.

For example, as shown in FIGS. 3-16 herewith, the ducts 34-34 may bearranged to discharge alternatively into the downspouts 36-36 or into acommon, rearwardly directed duct terminating in a discharge orifice 62at the rear end of the aircraft fuselage. A valve device as indicated at64, and pivotally mounted as shown at 65 (FIG. 16), may be convenientlyemployed under pilot control, to alternatively direct the compressoroutputs to either the downspouts 36-36 or the propulsion augmented duct60, as required.

As shown in FIGS. 8-14, the air intakes to the compressors 26-26 may beprovided through means of ducts 66 leading from louvered openings asindicated at 68-68 through the fuselage skin surfaces. As shown therein,louvers for alternately opening and closing the intake openings arepreferably employed, to enhance the aerodynamic surface of the fuselagewhen the compressors are inactive.

It is another feature of the present invention that the intake air forthe compressors 2626 may be conveniently drawn from the external surfaceof the fuselage at any preferred area thereof and at any preferreddegree therefrom, so as to simultaneously provide the requisitecompressor feed and at the same time to develop a preferred bounding airlayer control effect relative to the aircraft fuselage such as taughtfor example in US. Patent No. 3,100,539. Thus, as shown in FIG. 15herein, the compressor intakes may be arranged to draw air from betweena double walled fuselage construction; the outer wall 69 of which isperforated as preferred to permit controlled ingress of air through theouter skin structure of the fuselage (as shown by the air flow directionarrows of FIG. 15). Thus, the intake of air by the compressors 2626 notonly supplies the undercarriage mechanism and/or augments the propulsionpower units of the aircraft, but also enhances the aerodynamicefficiency of the aircraft fuselage through selective control of theboundary air layer relative thereto; it being understood that the meanscontrolling ingress of air through the outer skin structure of theaircraft will be selectively constructed and controlled, relative tovarious stations longitudinally and girthwise of the fuselage, so as toprovide the preferred boundary air layer control results.

It should be noted that, as shown in FIG. 16, whenever the valves 64 areadjusted to divert the compressor discharges into the rearwardlydirected propulsion-augmentation duct 60, an open space is providedbelow the valve plate pivot 65 through which air is automatically suckedup through the downspouts 36 from the interiors of the cells 30. 32.Thus, immediately upon becoming airborne, the airplane pilot may controlthe valves 6464 to move them to their broken line positions as shown inFIG. 16. The compressor outputs will thereupon augment the propulsionengine outputs and will at the same time induce evacuation of the cells30, 32; whereby the latter will quickly retract into fuselagehuggingconfigurations, enhancing the climb-out maneuver.

FIG. 15 illustrates a further modification of the air flow controlsystem of the invention, wherein a portion of the rearwardly directedcompressor discharge is bypassed through conduits 7070 intodouble-walled chambers 72-72 at the rear of the aircraft. The outer wallportions of the fuselage in the regions of the chambers 72-72 areperforated to permit the compressor-driven air to bleed therethrough andthus feed the boundary air layers externally of those portions of thefuselage. Thus, it will be appreciated, by means of the examples shownand described, that any desired boundary air layer control effect may beeasily attained at any desired area of the aircraft fuselage. as asupplement to and in augmentation of the primary objects and beneficialresults of the present invention.

FIGS. 5, 6, 7, illustrate how the inflated cells 3032 enhance thelanding and take-off maneuvers of the airplane. As shown at the lefthand end portion of FIG. 5, the airplane may fly in for a landing innormal horizontal attitude until it settles into such close proximity tothe landing surface that the ground effect forces assume verticalsupport of the craft. The propellers (or the jet thrust controls) maythen be reversed, or brakes lowered. or the like. to bring the craft toa standing or taxiing attitude. as shown at the right hand end portionof FIG. 5. The central portion of FIG. illustrates how the craft may becontrolled to drag the rear end of the cell 32 on the landing strip forbraking purposes. if desired. FIG. 6 illustrates how the craft ismaneuvered during a take-off run and climb-out. At the right hand end ofFIG. 6 the craft is starting the take-off run. At the center portion ofthe figure the nose is being lifted, and as shown in FIG. 7, at thisstage of the operation the rear cell 32 is supplying the maximum groundeffect support for the craft at the heel end portion of the cell. Thefront cud of cell 32 is lifted away from the reaction surface and isfreely spilling its air content, and is relatively relaxed and normal inconfiguration; while the rear end portion of cell 32 is carrying theremaining brunt of the air cushion support load and is accordingly undergreater pressures in all directions. However, the fabric of the cellstructure is preferably of such nature as to be elastic in girthwisedirections only, whereby the heel portion of the cell 32 will, undertake-off conditions, compact itself somewhat vertically withoutsubstantial drag-out at the rear end thereof (FIG. 7). The abovedescribed adjustments of the cell configuration take place while at thesame time the bottom profile portion of the cell continues to adapt andconform itself to the changing attitude relation to the landing surface.That is, the bottom peripheral portion of the cell remains in slightlyspaced relation to the reaction surface, thereby providing the requisitevertical support of the aircraft while avoiding damaging frictionalcontacts with the reaction surface.

Whereas only a few forms of gas-cushion cell arrangements have beenillustrated and described hereinabove by way of example, it will ofcourse be appreciated that a variety of other cell arrangements (inregard to cell planform shapes and number of cells and relative planformdispositions thereof) may be employed. FIGS. 34 for example show merelya preferred cell arrangement which embodies the use of two cells intandem relation as illustrated at 30, 32. The larger cell 32 isapproximately centered (longitudinally of the craft) slightly behind theoverall center of gravity of the airplane, while the smaller cell 30 islocated forwardly thereof; thereby simulating the arrangement of atricycle type wheeled undercarriage and providing the craft with similarlanding and takeoff handling characteristics from the pilot standpoint.However, it is to be understood that any other preferred number andshape of cells may be employed. and in any other preferred planforrnrelationship, in order to support the airplane and provide the preferredlanding, taxiing, and takeoff handling characteristics. Also, it is tobe understood that if desired, the undercarriage system hereinillustrated and described may be supplemented by means of suitableoutrigger support devices such as pad or Wheel or float carrying strutsselectively employable to support the airplane when at rest relative toa landing surface with the compressor system idle.

Thus, it will be appreciated that by virtue of the present invention anundercarriage system for airplanes is provided which featureselimination of need of any wheeled or otherwise structurally rigidexternally projecting components'. employing in lieu thereof analternately inflatable-deflatable elastic balloon-like cell arrangementcircumscribing an air cushion space beneath the belly of the fuselage.Hence, the airplane is adapted to land relative to any reasonably flatsurface, although the latter may be unpaved and in fact may comprisenothing more than soft dirt, water, or the like; and is capable oflanding and taking ofl relative thereto without actual contacts with thesurface, being supported by a matter of inches thereabove. Furthermore,the invention features selective utilization of air compressor mechanismcarried by the aircraft to render the undercarriage mechanism operativeand alternatively for augmenting propulsion of the aircraft and/orproviding improved control of the boundary air layer externally of theaircraft fuselage; and it is to be understood of course that althoughonly a few forms of the invention have been illustrated and described indetail hereinabove. various changes may be made therein withoutdeparting from the spirit of the invention or the scope of theaccompanying claims.

\Ve claim:

1. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like shape. means carried within the airplane for deliveringrelatively low pressure gas into said cell and thereby inflating saidcell into an extended balloon-like form circumscribing a gas cushionspace under the airplane fuselage, said cell being formed with gasoutlet openings aligned peripherally of the bottom contour of said cellwhen inflated, elastically closed valve means associated with the outletopenings of said cell and means for delivering relatively high pressuregas to said valve means for actuating the latter to open conditionwhereby to permit gas to blast through said outlet openings and to feedsaid gas cushion space with pressured gas for generation of airplanesupporting ground effect forces whenever the airplane is disposed inclose proximity to a reaction surface.

2. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like shape, air-compressor means carried within the airplane forpumping air into said cell and inflating said cell into extendedballoon-like form thereby circumscribing an air cushion space under theairplane fuselage, said cell being formed with air outlet openingsaligned peripherally of the bottom contour of said cell when inflated,valve means associated with the outlet openings of said cell, and meanscarried by the airplane for actuating said valve means to open conditionwhereby to permit air to blast through said opening and to feed said aircushion space with pressured air for generation of airplane supportingground effect forces whenever the airplane is disposed in closeproximity to a reaction surface.

3. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like shape, compressor means carried within the airplane forpumping gas into said cell and inflating said cell into extendedballoon-like form thereby circumscribing a gas cushion space under theairplane fuselage, said cell being formed with gas outlet openingsaligned peripherally of the bottom contour of said cell when inflated,valve means associated with the outlet openings of said cell, and meansfor actuating said valve means to open condition whereby to permit gasto blast through said openings and to feed said gas cushion space withpressured gas for generation of airplane supporting ground eflect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

4. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like form, air compressor means carried within the airplane fordrawing air from externally of the airplane fuselage and pumping it intosaid cell and inflating said cell into extended ballon-like form therebycircumscribing an air cushion space under the airplane fuselage, saidcell being formed with air outlet openings, valve means associated withthe outlet openings of said cell, and means for actuating said valvemeans to open condition when said cell is inflated whereby to permit airto blast through said openings and to feed said air cushion space withpressured air for generation of airplane supporting ground effect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

5. In an airplane, in combination, an elastic cell structure attached tothe airplane fuselage and adapted to be inflated into a balloon-likeform, air compressor means carried within the airplane and having airintake means in communication with a duct device leading to theaerodynamic skin surface of said fuselage for drawing air fromexternally of the airplane fuselage and pumping it into said cell andinflating said cell into extended balloon-like form therebycircumscribing an air cushion space under the airplane fuselage, saidduct device having openable-closeable louver means in alignment with thefuselage skin profile for controlling inlet of air to said duct, saidcell being formed with air outlet openings, valve means associated withthe outlet openings of said cell, and means for actuating said valvemeans to open condition when said cell is inflated whereby to (illpermit air to blast through said openings and to feed said air cushionspace with pressured air for generation of airplane supporting groundeffect forces whenever the airplane is disposed in close proximity to areaction surface.

6. In an airplane, an elastic cell structure attached to the airplanefuselage and adapted to be inflated into a balloon-like form, saidfuselage having an air pervious skin portion, air compressor meanscarried within the airplane for drawing air from externally of theairplane fuselage through said skin portion and pumping it into saidcell and inflating said cell into extended balloon-like form therebycircumscribing an air cushion space under the airplane fuselage, saidcell being formed with air outlet openings, valve means associated withthe outlet openings of said cell, and means for actuating said valvemeans to open condition when said cell is inflated whereby to permit airto blast through said openings and to feed said air cushion space withpressured air for generation of airplane supporting ground effect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

7. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like form, a branch duct carried within said fuselage and havingone branch portion thereof arranged to deliver into said cell structureand another branch portion thereof arranged to deliver into theatmosphere rearwardly of said fuselage, air compressor means carriedwithin the airplane for drawing air from externally of the airplanefuselage and pumping it into said branch duct and selectively into saidcell for inflating said cell into extended balloon-like form therebycircumscribing an air cushion space under the airplane fuselage andalternatively rearwardly of said fuselage, said cell being formed withair outlet openings, valve means associated with the outlet openings ofsaid cell, and means for actuating said valve means to open conditionwhen said cell is inflated whereby to permit air to blast through saidopenings and to feed said air cushion space with pressured air forgeneration of airplane supporting ground effect forces whenever theairplane is disposed in close proximity to a reaction surface.

8. In an airplane, an elastic cell structure attached to the airplanefuselage and adapted to be inflated into a balloon-like shape, a branchduct leading to said cell and to a position of discharge directedreawardly of the airplane, air-compressor means carried within theairplane for pumping air into said branch duct and under control of avalve device alternatively into said cell for inflating said cell intoextended balloon-like form thereby circumscribing an air cushion spaceunder the airplane fuselage or rearwardly of said fuselage, said cellbeing formed with air outlet openings aligned peripherally of the bottomcontour of said cell when inflated, valve means associated with theoutlet openings of said cell, and means carried by the airplane foractuating said valve means to open condition whereby to permit air toblast through said openings and to feed said air cushion space withpressured air for generation of airplane supporting ground effect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

9. In an airplane, an undercarriage comprising an elastic cell structureattached to the airplane fuselage and adapted to be inflated into aballoon-like shape, a branch duct leading to said cell and to a positionof discharge directed rearwardly of the airplane, compressor meanscarried within the airplane for pumping gas into said branch duct andunder control of a valve device alternatively with said cell andinflating said cell into extended balloon-like form therebycircumscribing a gas cushion space under the airplane fuselage orrearwardly of said fuselage, said cell being formed with gas outletopenings aligned peripherally of the bottom contour of said cell wheninflated, valve means associated with the outlet openings of said cell,and means for actuating said valve means to open condition whereby topermit gas to blast through said openings and to feed said gas cushionspace with pressured gas for generation of airplane supporting groundeflect forces whenever the airplane is disposed in close proximity to areaction surface.

10. In an airplane. an undercarriage comprising an elastic cellstructure of toroidal plan form attached to the airplane fuselage andadapted to be inflated, compressor means carried within the airplane forpumping air into said cell and inflating said cell into extendedballoon-like form thereby circumscribing an air cushion space under theairplane fuselage, said cell being formed with air outlet openingsaligned peripherally of the bottom contour of said cell, valve meansassociated with the outlet openings of said cell, and means foractuating said valve means to open condition when said cell is inflatedwhereby to permit air to blast through said openings and to feed saidair cushion space with pressured air for generation of airplanesupporting ground eflect forces Whenever the airplane is disposed inclose proximity to a reaction surface.

11. In an airplane, an elastic cell structure attached to the airplanefuselage and adapted to be inflated into a balloon-like shape, a branchduct leading alternatively to said cell and to a position of dischargedirected rearwardly of the airplane, compressor means carried within theairplane for pumping air into said branch duct, a flip-flop valve devicefor controlling flow of compressed air through said branch ductalternatively rearwardly of said fuselage, or into said cell forinflating said cell into extended balloonlike form wherebycircumscribing an air cushion space under the airplane fuselage, saidcell being formed with air outlet openings aligned peripherally of thebottom contour of said cell when inflated, valve means associated withthe outlet openings of said cell, and means carried by the airplane foractuating said valve means to open condition whereby to permit air toblast through said openings and to feed said air cushion space withpressured air for generation of airplane supporting ground effect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

12. In an airplane, an elastic cell type undercarriage structureattached to the airplane fuselage and adapted to be inflated into aballoon-like shape to stand away from said fuselage, a branch ductleading alternatively to said cell and to a thrust outlet directedrearwardly of the airplane into the ambient atmosphere, compressor meanscarried within the airplane for pumping air into said branch duct, 21valve device for selectively controlling fiow of compressed air throughsaid branch duct either through said thrust outlet or into said cell forinflating said cell into extended balloon-like form, said valve devicebeing disposed in said branch duct in such manner as to induce flow ofair from said cell through said duct to said thrust outlet when saidvalve device is set to deliver compressed air to said thrust outletthereby causing deflation and collapse of said cell intofuselage-hugging condition, said cell being formed with air outletopenings, valve means associated with the outlet openings of said cell,and means for actuating said valve means to open condition whereby topermit air to blast through said openings for generation of airplanesupporting ground effect forces Whenever the airplane is disposed inclose proximity to a reaction surface.

13. In an airplane, an undercarriage comprising a plu rality of elasticcell structures attached to the airplane fuselage and adapted to beinflated into balloon-like shapes, means carried Within the airplane fordelivering relatively low pressure gas into said cells and therebyinflating said cells into extended balloon-like forms circumscribing gascushion spaces under the airplane fuselage, said cells being formed withgas outlet openings aligned peripherally of the bottom contours of saidcells when inflared, elastically closed valve means associated with theoutlet openings of said cells and means for delivering relatively highpressure gas to said valve means for actuating the latter to opencondition whereby to permit gas to blast through said outlet openingsand to feed said gas cushion spaces with pressured gas for generation ofairplane supporting ground elfect forces whenever the airplane isdisposed in close proximity to a reaction surface.

14. In an airplane, an undercarriage comprising a plurality of elasticcell structures of toroidal plan forms attached to the airplane fuselageand adapted to be inflated into balloon-like shapes, means carriedwithin the airplane for delivering relatively low pressure gas into saidcells and thereby inflating said cells into extended balloon-like formscircumscribing gas cushion spaces under the airplane fuselage, saidcells being formed with gas outlet openings aligned peripherally of thebottom contours of said cells When inflated, valve means associated withthe outlet openings of said cells and means for delivering relativelyhigh pressure gas to said valve means for actuating the latter to opencondition whereby to permit gas to blast through said outlet openingsand to feed said gas cushion spaces with pressured gas for generation ofairplane supporting ground eflect forces whenever the airplane isdisposed in close proximity to a reaction surface.

15. In an airplane, an undercarriage comprising a pair of longitudinallytandem elastic cell structures attached to the airplane fuselage andadapted to be inflated into balloon-like shapes, means carried withinthe airplane for delivering relatively low pressure gas into said cellsand thereby inflating said cells into extended balloon-like formscircumscribing gas cushion spaces under the airplane fuselage, saidcells being formed with gas outlet openings aligned peripherally of thebottom contour of said cells when inflated, elastically closed valvemeans associated with the outlet openings of said cells and means fordelivering relatively high pressure gas to said valve means foractuating the latter to open condition whereby to permit gas to blastthrough said outlet openings and to feed said gas cushion spaces withpressured gas for generation of airplane supporting ground effect forceswhenever the airplane is disposed in close proximity to a reactionsurface.

16. In an airplane, an undercarriage comprising a pair of longitudinallytandem elastic cell structures of closed circumferential plan formsattached to the airplane fuselage and adapted to be inflated intoballoon-like shapes, one of said cell structures comprising a relativelylarge cell disposed substantially under the center of gravity of theairplane and the other of said cells comprising a relatively small celldisposed ahead of said larger cell, means carried within the airplanefor delivering relatively low pressure gas into both said cells andthereby inflating said cells into extended balloon-like formscircumscribing separate gas cushion spaces under the airplane fuselage,each of said cells being formed with gas outlet openings alignedperipherally of the bottom contour of said cells when in flated, valvemeans associated with the outlet openings of said cells and means foractuating said valve means to open condition whereby to permit gas toblast through said outlet openings and to feed said gas cushion spaceswith pressured gas for generation of airplane supporting ground effectforces whenever the airplane is disposed in close proximity to areaction surface.

17. An aircraft capable of landing, talrc-ofl and taxiing over roughterrain comprising, in combination,

on aerodynamic fuselage, propulsion. means and a1 wing for sustainingthe aircraft in flight,

a cell structure of elastic sheet material secured to the underside ofsaid fuselage, .Yflltl ccll structure being elastic in girllrwircdirections and dimensioned to retract resiliently of its Ult'll accordinto Iautened fuselage-cantonr-confurming condition, whereby it isdisposed normally in retracted condition compatible with the aerodynamicshape of said fuselage, means for supplying said cell structure withpressurized fluid to inflate said cell structure downwardly of saidaerodynamic shape of the fuselage to define a fluid cushion spacebounded laterally by said downwardly inflated cell structure,

and said cell structure including means for producing a jet curtain offluid issuing downwardly and inwardly from said cell structure whichcircumscribes said fluid cushion space.

18. In the aircraft as defined in claim 17 wherein said material iselastic to retract resiliently of its own accord intofuselage-contour-conforming condition.

19. An aircraft capable of landing, take-off and taxiing over roughterrain comprising in combination,

an aerodynamic fuselage, propulsion means and a wing for sustaining theaircraft in flight,

a cell-like device of flexible wall form secured to the underside ofsaid fuselage and having flexible wall portions, said wall portionsbeing elastic in girth-wise directions and dimensioned to retractresiliently into tautened fuselage contour conforming condition, wherebythe cell-like device is disposed normally in retracted conditioncompatible with the aerodynamic shape of said fuselage,

and means for supplying said cell-like device with pressured fluid toinflate said cell-like device and extend said elastic wall portionsthereof below said fuselage to define in cooperation with said fuselagea fluid cushion space bounded laterally by said cell-like derice, saidcell-like device having openings for producing a jet curtain of fluidissuing downwardly and inwardly from said cell structure whichcircumscribes a fluid cushion space bounded laterally by said celllikedevice when inflated.

20. An aircraft as defined in claim 19 including means for directingpressured fluid directly into the confines of said fluid cushion space.

21. In an airplane, an undercarriage comprising an elastic cellstructure attached to the airplane fuselage and adapted to be inflatedinto a balloon-like shape, means carried within the airplane fordelivering relatively low pressure gas into said cell structure andthereby inflating said cell structure into an extended balloon-like formcircumscribing a gas cushion space under the airplane fuselage, saidcell structure being elastic in girth-wise directions and dimensioned toretract resiliently of its own accord into fuselage-contour-conformingcondition when deflated, said cell structure being formed with gasoutlet openings peripherally of the bottom contour of said cellstructure when inflated to permit gas to blast through said outletopenings and to feed said gas cushion space with pressured gas forgeneration of airplane supporting ground efiect forces whenever theairplane is disposed in close proximity to a reaction surface.

References Cited The following references. cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 1,536,283 5/1925 Breguet 244- 3,082,976 3/1963Dornier 244-12 3.102,705 9/1963 Namsick 244-102 3,124,322 3/1964Cockercll 244-12 3,253,666 5/1966 Kiel-nan et a1. 180-122 3,279,55410/1966 Hunt 180-127 3,297,280 1/1967 Lee 244-105 3,363,717 1/1968 Hunt-128 3,357,514 12/1967 Jones 180-128 3.117,?47 1/1964 Creascy et a1.244-12 3,128,970 4/1964 Tinajcro et a1 244-100 FOREIGN PATENTS 1,393,9102/1965 France.

MILTON BUCHLER, Primary Examiner PAUL E. SAUBERER, Assistant Examiner

